The Zcd has fixed and variable line outputs as well as coaxial and optical digital audio outputs and the Zcd volume adjustments are controlled by an independent analog volume control IC, not digitally inside the DAC.
The Zcd uses a 24-bit, 192 kHz-capable Cirrus Logic CS4353 DAC with a Cirrus Logic CS8416 digital receiver. The circuitry boasts fifth-order multi-bit delta-sigma architecture with low latency digital filtering. It also includes analog filtering and differential linearity along with a high tolerance to clock jitter.
For custom installers, the Zcd has a rear-panel IR input and one-way RS232 serial control port. There are three turn-on options: manual, automatic when AC is supplied, and 12V trigger. There is even a 12V trigger output to turn on a Zamp v.3 amplifier automatically.
Go here for all the specs: http://www.parasound.com/ParasoundZ/